Firmament? Is it real? I've experienced it

In THIS video I have to confess that I believe in the Firmament because I've experienced it. If I've experienced something, then I have to say I believe in it- right? And I really don't want to go that far cuz it (The Firmament) sounds crazy, right? Even to me! I'm still not on board with Flat Earth or Crop Circles. At least for now.
What's really going on around here? THIS channel is a start to that discussion.